Effect of Zircoat-M coating on SS304L for designing high temperature process chamber in selective laser sintering

Abstract

Selective laser sintering (SLS) process is one of the most useful additive manufacturing techniques used, because it has the ability to readily generate complicated structures. The quality of parts made by SLS process directly depends on controlling heat transfer to powder bed. High temperature process chamber is specially designed for high temperature plastics and metal powders (PEEK and Aluminium). With the exception of aluminium, Zircoat - M is a Zirconia-rich refractory coating compound with a high proportion (63%) of Zirconia and is best suited for ferrous and non-ferrous metals and refractories. Metals and refractories are protected by Zircoat-M from corrosion erosion and flue gases escaping from heating chambers. An attempt was made to develop a high temperature build chamber and pre-heating system to manufacture prototypes using materials having maximum melting/ fuse temperature of 800°C. PEEK and Aluminium may be used to produce light weight products for multiple sectors such as bio-medical, automobile and aerospace. A high temperature resistant stainless steel 304L grade was chosen, along with SS304L coated with Zircoat-M for Build chamber and Pre-heating system. Experimental analysis such as Thermal Expansion, Thermal Conductivity and Corrosion resistance for the coated and uncoated specimen was carried out. Coefficient of Linear Thermal Expansion of uncoated specimen is 16 × 10-6 /°C and coated specimen is 14 × 10-6 /°C. Thermal conductivity for the Ceramic coated Zircoat-M on SS304L for 100 °C is 0.280 W/mK. Thermal conductivity of SS304L at 100 °C is 16.3 W/mK. Both the specimen has very good corrosion resistance.